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Common Angelfish Diseases
Common Angelfish Diseases - by Debbie Bottle

Parasitic and Protozoan

  • Hole-In-The-Head
  • Internal Parasites
  • Gill Flukes
  • Ich


  • Bacterial

  • Hemorrhagic Septicemia
  • Fungus
  • Fin and Tail Rot
  • Pop-eye
  • Bloat-Dropsy


  • This is a general disease chart of “some” of the common diseases or parasites that Angelfish can contract. These are treatments for Angelfish ONLY. Some fish can not withstand some of the treatments that I am suggesting for treating Angelfish.

    I am not an expert at fish diseases but have had to deal with some of these things with my own fish at times. I can only tell you what worked for me when treating for these different diseases and parasites. Hopefully these things will be of help to some of you that are having problems with your fish.

    #1. Hole-In-The-Head – HITH is caused by Flaggelates that live in the fish's gut. When the fish is under stress these flaggelates will multiply which will make the fish sick.
  • Symptoms – Fish stop eating, will hide or face the back of the tank, feces look white and stringy. In its advanced stages holes will start to show in the head and gill area.
  • Treatment – High temperatures between 88 degrees – 98 degrees F. and the medication Metronidozole should be used for treatment.


  • #2. Internal parasites – This could be flaggelates, or it could be worms.
  • Symptoms - Some of the symptoms are the same with both of these parasites. White stringy feces, fish stop eating and the fish may be hiding or separating itself from the other fish.
  • Treatment - There are also different types of worms that fish can contract. Without going into all of the different types of worms there are in fish, the best treatment for worms that I have found is Levasole. It is used in de-worming farm animals, such as pigs, goats and sheep. This product can be either purchased on line or at your local Farm and Tractor Supply store.


  • #3. Gill Flukes – Is an external parasite.
  • Symptoms - Fish rapidly pumps its gills open and shut, hangs at the surface of the water, becomes lethargic and will sometimes “flash” off of tank decorations like they are trying to scratch an itch. Gills become pink and may show mucous.
  • Treatment can be done with “Coppersafe”, Prazi Pro or Parasite Clear by Jungle. Not limited to those medications but just to name a few.


  • #4. Ich (Ichthyophthirius multifilis) – Is an external parasite.
  • Symptom - When it finds a host (your fish) you will see tiny white pimples that look like grains of salt on your fish.
  • Treatment – If you want to go the route of not using harsh chemicals you can simply up the temperature in your tank to over 86 degrees F. and treat with non-iodized salt by using 2 Tablespoons of salt per 10 gallons of water, or make a strong bath of salt solution as a dip. If you have invertebrates or scaleless fish such as loaches, snails, plecos…etc. you will have to remove them before the salt treatments. Even with some chemical treatments it will tell you to not use on certain types of fish or invertebrates so please read the instructions on the bottle. To name a few chemical treatments for Ich - there is Quick Cure. Malachite Green and Methylene Blue can be used and can be sold under different name brands for Ich medication. Treatments must be given long enough to ensure that all of the parasites are gone. Once the parasite has embedded itself in your fish, the medications will not kill the parasite, but once the parasite releases itself from its host and is free swimming then the medication will do its job. That is why the treatment should last 10 – 14 days. Watch carefully for other infections, as secondary infections often occur once the parasite has damaged the skin on your fish.


  • #5. Hemorrhagic Septicemia – Is a bacterial infection and is VERY contagious.
  • Symptoms are red blood streaks in fins and/or on the body of the fish. Fish can act lethargic with this also.
  • It is a fast killing infection that can spread rapidly through your tank to other fish. When working in an infected tank be sure to sterilize anything that comes in contact with the tank water such as nets, siphons, plants and decorations and…even your hands and arms before putting them into another tank.
  • Treatment - In my opinion the best treatment for this is Oxytetracycline. There may be other medications that help cure this also, but the Oxytetracycline works fairly fast from my experience with it.


  • #6. Fungus – Looks like cotton on a wound of a fish. If not treated early it can be fatal to the fish.
  • Symptoms - Signs can be grey/white patches on skin or gills of the fish that look like cotton or wool.
  • Treatment - This can be treated with a salt bath or by adding salt to the tank water and/or using Malachite Green.


  • #7. Fin and Tail Rot – Loss of fin tissue that results in ragged or split fins.
  • Symptom - It is usually the edges of the fins that are effected but a hole my sometimes appear in a fin also. In advanced cases there maybe some reddening or inflammation. Fin rot is a bacterial disease and is usually brought on by stress or by not giving the fish sanitary conditions, overcrowding, parasites or low oxygen levels. Secondary infections are not uncommon with fin and tail rot.
  • Treatment - The best treatment would be to relieve the stress on the fish by giving it a clean environment and adequate room in the tank. Adding salt to the tank would also help with healing or by adding Melafix.


  • #8. Popeye, Bloat/Dropsy – I put all 3 together because a lot of the times I’ve seen a fish get all of these things at once in the more advanced stages.
  • Sypmtoms - The eyes of the fish will look like they are bulging out of the eye sockets and in some cases the fish will be bloated in the stomach area. In some cases the scales of the fish will stick out (sort of like looking at a pine cone). This problem is usually brought on by bacterial infections. Some fish my even have ulcers that form.
  • Treatment - I’ve treated the onset of Popeye with Melafix with great results, but if it is more advanced then stronger medications will have to be used. A short term bath of potassium permanganate for a few hours each day may be of some help. Medicated antibiotic food can be fed to the fish if (of course) the fish is still eating. Antibiotics can be added to your tank water to help cure this. If the fish is in some very advanced stages to where the fish is very bloated and can not swim normally, the swim bladder may be affected or the fish has gone into kidney failure and will probably not recover.


  • How do I cycle my new tank?
    My First Angelfish Tank – MTHatchery (James)

    Things you need to know, to do, and that you need to have to cycle your first angelfish aquarium. This is how to do it when you don’t have a healthy tank to take water, sponge filters, or substrate from.

  • 1. Make sure you have your Ph, Ammonia, Nitrite, Nitrate, Chlorine, Gh, and Kh test kits before you start. Otherwise you won’t have the information you need to lower the risk of the fish not surviving the tank cycle.


  • 2. Test your tap water to find out what you have to work with. If the water is hard with a high Ph reading you may want to purchase RO water to blend with it to lower the hardness to about 50ppm until you have the tank cycled. This will make it easier to lower the Ph to between 6.0 and 6.5 until the ammonia stage of the cycle is complete. This is important because it will determine if the fish survive or are killed by the ammonia present. The same amount of ammonia that is safe at a Ph of 6.0 would kill the fish quickly at a Ph of 7.5 to 8.0 and that is something you don’t want to forget.


  • 3. If you are using some of the chemical treatments for chlorine and ammonia you can not use a Nesslers type ammonia test kit or you will get false high readings so make sure your test kit is compatible with whatever product you use.


  • 4. When the nitrites start to rise the ammonia will drop quickly. When the nitrites start to show with your test kit add 1 tbsp of aquarium salt per 5 gals to the aquarium to help prevent nitrite poisoning and raise the Ph to between 6.5 and 7.0.


  • 5. Once you start to see the nitrates start to show with your test kit the cycle is about complete and the fish should be fine and no longer in danger. Your normal water changes should keep everything within limits with proper stocking levels.


  • 6. When the cycle is complete you should be able to use your tap water to maintain angelfish in most cases if it is of reasonable quality. Angelfish can survive at a higher Ph once the ammonia is all gone from the tank but not until then.


  • 7. Do not fill your tank and add the water treatments then allow it to set empty without fish for more than 24 hours or you will have a bacterial bloom of a kind you don’t want. The phosphates and sulfates often found in such products are food for the bacteria and without fish present you will be growing the types of bacteria that you don’t want.


  • 8. Remember it will take a few days after the fish are added before the ammonia starts to rise so don’t think because you don’t see any rise in the ammonia level within the first couple of days that your tank has cycled. That would be a big mistake that you don’t want to make.


  • 9. Pay close attention to the fish to see if they appear to be stressed and test the water daily until you are positive that the tank has cycled. If the fish appear to be fine then keep your water changes to a minimum only removing the fish waste until the tank has cycled. Making large water changes while the tank is cycling only extends the time it takes to get the tank cycle complete and only adds stress to the fish. Of course if you have a major setback in the cycling process you may have to make a large water change to save the fish but that situation is rare and usually comes from poor planning or misunderstanding the cycling process.


  • 10. Adding products to help the tank cycle is fine but be aware that as the bacteria number increases it requires more oxygen for the bacteria and you need to be careful that the fish don’t die from oxygen depletion. That means don’t add too much of the product thinking it will help the tank cycle more quickly or you may kill the fish.


  • 11. Use an acid based liquid to lower the Ph if possible because many of the powders contain phosphates and sulfates which will cause bacterial and algae blooms. I use muriatic acid for the purpose always being careful when using such products. It only takes very little to do the job if the water hardness is lowered to around 50 ppm which is a good range to cycle a tank. The Ph is stable there but can be lowered easily as needed.


  • 12. If you want to add your tap water and allow the water to age overnight don’t add the treatment chemicals until a few hours before you add the fish at most.


  • 13. Remember if using public supplied tap water to always test it before adding it to your tank to be sure nothing new has been added that could kill your angelfish. That has happened many times when the treatment process was changed from chlorine to chloramines and the fish keeper didn’t realize it.


  • 14. Something to be very careful of when cycling a tank using hard water with a Gh and Kh over 150 ppm is trying to lower the Ph and expecting it to stay down to protect the fish. This is very risky because while you may be able to lower the Ph the amount needed and the fish may seem fine in a very short time the Ph will start to rise again and that could be deadly. As the Ph rises the ammonia present will be converted from NH4 to NH3 and could quickly kill the fish. This has happened many time where someone thought everything was alright and when they returned from work found the Ph had risen above 7.0 and all the angelfish were dead. So be very careful not to let that happen if trying to cycle a tank using hard water.


  • How do I pick out healthy Angelfish?
    How do I pick out healthy Angelfish?

    When you go into your local fish store or even at a breeder's hatchery and you are looking for Angelfish to bring home, make sure you look them over very good, and also every other fish in the tank. I highly recommend to NOT purchase any fish that is in a tank with other sick fish, or in a tank that has dead fish in it. Most likely the other fish will eventually come down with the disease or bring the disease home to your own tanks and fish.

    Look at the fins of the Angelfish for any ragged looking fins or white spots on the fish or anywhere on the body. The fins of the Angelfish should be spread open, not clamped. Clamped fins are a sign that the fish is under stress.

    Look at the gills. If they are flared open or the fish is breathing heavily, that is not a good sign.

  • Tiny white spots that look like grains of salt are Ich (a parasite).
  • White cottony patches on the fish is fungus.
  • Red streaks in the fins or on the body could mean a bacterial infection and the fish is bleeding internally.


  • More things to look for would be; Is the fish swimming around or is it facing the back of the tank or off by itself in a corner or behind a plant? If the fish is hiding or off by itself then that is not a good sign and I would not purchase the fish. One thing I do is act like I’m going to feed them. Hold your hand above the tank and see how the fish react. If they are healthy Angelfish they will be alert and will go to the top looking for food. They think you are going to feed them. If they do not react, then something could be wrong with them. Healthy Angelfish will always be ready to eat. You could even ask the pet shop owner or an employee to drop a bit of food in the water so you can make sure they are eating good.

    If the fish looks alert, has clear eyes and is swimming around and not hiding and you’ve checked the fish out by looking for the suggested “things to look for” in the above paragraphs…most likely the fish is ok. I would still highly recommend putting the fish in a quarantine tank for around 3 weeks before adding the fish into your tank with your other healthy fish. It’s better to always be safe than sorry.

    Debbie Bottle

  • How can I tell the sex of my Angelfish?
    There are some subtle differences that an experienced angelfish breeder can use to help identify mature males and females. The only sure way to distinguish mature males from mature females is to examine the breeding tubes during spawning. The female's breeding tube is wider and more blunt than the male's. Some describe the female’s breeding tube as looking like an eraser on a pencil and the male’s breeding tube is pointy like the sharpened end of a pencil. In some mature male Angelfish, they may show some other small differences. For instance, some may have a hump on the crown and some may be larger than the females, but this is not always the case.

    How many Angelfish can I keep in my tank?
    Depending on your water changing schedules (the frequency and volume of water you change), the amount of food that is fed and the type of filtration you have and the temperature you keep them at will determine allowable density for raising Angelfish. Of course, the more Angelfish you have in a tank the more frequent water changes you should do. If you want high quality looking Angels I would recommend starting by giving any that are over dime sized, at least 3 gallons per Angelfish. If over quarter sized, try to give them 7 gallons per Angelfish. Once they are mature and start to breed, it is best if you can give them 10 gallons of water per Angelfish.

    Bare bottom tank VS Gravel?
    Gravel is normal for show tanks, however it is not considered the best thing for breeding situations. Any tank with angelfish fry in it should be a bare bottom tank. The small food that fry need, will fall into the gravel where it can't be eaten and it will decompose, causing bacterial problems in the tank. For tanks with fry, it is recommended that a small pore sponge filter be used for filtration.

    What other fish can I keep with my Angelfish?

    Angelfish seem to do best with other Angelfish. The reasons are that some fish carry diseases that are not an obvious problem with them, but can be very harmful to Angelfish. Without the proper quarantine procedures you can introduce these diseases to your Angelfish and cause them great harm or death. ALL new fish should be quarantined whether they are new Angelfish or any other types of fish that will be going into your healthy tank.

    There are a few types of other fish that do well with Angels. Bristlenose Plecos, Cory Cats, Discus, Festivums, urarus and some tetras that can’t be eaten by Angels and are not fin nippers.



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